Right after ZA updated the other night, my computer bogged down and locked up. After waiting to see if it would clear, I shut down and rebooted. I started getting error messages that an application or dll was not a valid windows image, and then when I tried to open programs, I got a message that each program was not a valid WIN32 program. After rebooting in safe mode and running every scan program imaginable to find a problem with no results, I wondered if it was ZA. I rebooted in normal mode and the same problem was happening, so then I rebooted in normal mode again, but exited ZA as soon as the icon came up in the tray. No problems without ZA running! Has anyone else encountered this?

This issue could be due to ZoneAlarm not being compatible with Media Center.
What you can do is format reinstall of Windows, Windows Updates to Service Pack 3 and then install the latest version of ZA then see if the issue still occurs, if it does then it is probably an incompatibility with your Media Center OS.